Paul 'Fitzy' Fitzgerald

Nick Stevens's alter ego works the parking lot at Gillette Stadium

Paul "Fitzy" Fitzgerald is foul-mouthed, sports-obsessed, and capable of letting off a belch that is roughly the length of an Eddie Van Halen guitar solo.

And Pats fans love him.

At least the ones who are calling out "Fitzy!" as he makes his way through the tailgate crowd before the Patriots' playoff game at Gillette Stadium last Sunday.

Fitzy, though, is not a real person. He is a character played by Nick Stevens, a comedian and actor originally from Braintree. Notorious for his webcasts on townienews.com, Fitzy is both a parody of, and an homage to, the beer-commercial version of the Boston sports fan, says Stevens, who once spent a year as the voice of Miller Lite commercials.

"He's that obscenity-spouting, beer-guzzling, Fenway Park bleacher creature that I love so much," says Stevens, 33, who now lives in, of all places, New York City (he studied film at New York University and stayed to work in the entertainment biz).

"Fitzy has the accent I used to have, wears the clothes I used to wear," says Stevens, outfitted in a red nylon Patriots jacket he got when he was a chubby 11-year-old. "Maybe he's a character. Maybe he's an ideal. Maybe he's just a chance to say the things I wish I could say."

This game is something of a milestone for Stevens, because it marks Fitzy's one-year anniversary of going online as a Boston sports commentator - the Fitzy character began life as a movie critic in a New York variety show seven years ago - as well as his return to friendly Foxborough, following a season on the road providing a PG-13 version of Fitzy for ESPN.com's Monday Night Football coverage.

So on this clear afternoon, Fitzy means to "spread a little good cheer" to his fellow fans, which, by Fitzy's definition, involves eating their food, drinking their beer, and insulting them - all of it captured by a video camera.

As Fitzy/Stevens moves through the gluttonous spreads along Route 1, he approaches a slim, goateed fan, sticks the microphone in his face, and says, "Did anyone ever tell you that you look like a white Tony Dungy?" referring to the Indianapolis Colts coach.

"The '80s called, and they don't want their pants back," he says to another fan wearing red, white, and blue animal-print sweatpants.

"What did you do, wake up in a Bud Light bathtub this morning?" he asks an aromatic fan grilling 20 pounds of moose meat with five other buddies from Maine.

For four hours, Stevens continues the charade with his younger brother, Geoffrey, following with the camera. Usually, the interviews are hilarious. Occasionally, they're weirdly uncomfortable - such as the one with a fan who pulls up his shirt to show off something he's painted on his chest, except that, in the pre-game revelry, he's apparently forgotten to paint it.

"He must write in chest hair," Stevens says, breaking character after the interview, "because that was an upsetting sight."

Remarkably, everyone in the crowd plays along, everyone laughs, everyone shakes Fitzy's hand after he delivers his signature sign-off, which is one of the most offensive things you can say to another human being and which can be seen, as its three-letter acronym, on many bumper stickers throughout the parking lots.

But it's not all an improv, gotcha gag. Stevens writes material ahead of time, creating talking points and one-liners to work with, and he stops occasionally to perform insightful "Fitzylogues" that offer commentary on his beloved Patriots - he has a pronounced man-crush on Tom Brady - and attacks on their foes, whether they be other teams or the media. (Fitzy's "Leave Bill Belichick Alone" webcast, a parody of the "Leave Britney [Spears] Alone" video that became a YouTube sensation, defended the coach's role in "Spygate" and has been viewed more than a million times.)

"He just sums up everything you think as a Patriots fan," says Alex Izzo, a cousin of Patriots linebacker Larry Izzo, who is such a Fitzy fan that she baked two dozen cupcakes for Sunday's game decorated with such Fitzyisms as "Totally Mossome" and "Your mom."

Fitzy, who first gained some notice with his Web commentaries in 2007, came in for criticism after some people figured out that he was not a real person, but played by an actor who lived in New York. But Stevens, who was discovered after he appeared as himself as a talking head on some of VH1's pop culture shows, says that the people who think he's mocking them are missing the reality that Fitzy is more like an alter ego than a character.

As the sun sets and the lights come on in the stadium for the night's game, Stevens is accosted by another fan as he prepares to wrap up for the night.

"You're that guy," the fan yells.

He is, indeed.

Correction: Because of an editing error, the "Hanging With" feature in yesterday's Sidekick incorrectly described the weather for the New England Patriots' AFC playoff game on Jan. 12. The weather was clear and dry.